The minute is a unit of time or of angle. As a unit of time, the minute is equal to 1⁄60 (the first sexagesimal fraction[1]) of an hour or 60 seconds. In the UTCtime standard, a minute on rare occasions has 59 or 61 seconds, a consequence of leap seconds. As a unit of angle, the minute of arc is equal to 1⁄60 of a degree or 60 seconds (of arc). Although not an SI unit for either time or angle, the minute is accepted for use with SI units for both.[2] The SI symbols for minute or minutes are min for time measurement, and the prime symbol after a number, e.g. 5′, for angle measurement. The prime is also sometimes used informally to denote minutes of time.

In old astronomical texts, minute can also mean a unit of time equal to 1⁄60 of a day (24 usual minutes). These minutes correspond to the Latin diei scrupulis, and used to express periods of planetary motions.[citation needed] For example, Kepler in Harmonices Mundi gives Saturn's year as 10759D12', that is 10759 (Earth) days, 4 hours, and 48 (usual) minutes (roughly 29.5 years).